Resource allocation for repetitions of transmissions in a communication system

ABSTRACT

Methods and apparatus are provided to define sub-bands within a downlink (DL) system bandwidth or within an uplink (UL) system bandwidth, to configure sub-bands for DL signaling or for UL signaling, and to transmit or receive DL signaling or UL signaling with repetitions in the configured sub-bands.

CROSS-REFERENCE TO RELATED APPLICATION AND CLAIM OF PRIORITY

The present application is a continuation of U.S. application Ser. No.15/063,148, filed Mar. 7, 2016, entitled “RESOURCE ALLOCATION FORREPETITIONS OF TRANSMISSIONS IN A COMMUNICATION SYSTEM”, now U.S. Pat.No. 9,887,801, which claims priority under 35 U.S.C. § 119(e) to: U.S.Provisional Patent Application Ser. No. 62/131,629 filed Mar. 11, 2015,entitled “RESOURCE ALLOCATION FOR REPETITIONS OF TRANSMISSIONS IN ACOMMUNICATION SYSTEM;” U.S. Provisional Patent Application Ser. No.62/201,172 filed Aug. 5, 2015, entitled “RESOURCE ALLOCATION FORREPETITIONS OF TRANSMISSIONS IN A COMMUNICATION SYSTEM;” U.S.Provisional Patent Application Ser. No. 62/207,439 filed Aug. 20, 2015,entitled “RESOURCE ALLOCATION FOR REPETITIONS OF TRANSMISSIONS IN ACOMMUNICATION SYSTEM;” and U.S. Provisional Patent Application Ser. No.62/246,852 filed Oct. 27, 2015, entitled “RESOURCE ALLOCATION FORREPETITIONS OF TRANSMISSIONS IN A COMMUNICATION SYSTEM.” The contents ofthe above-identified patent documents are incorporated herein byreference.

TECHNICAL FIELD

The present application relates generally to wireless communicationsand, more specifically, to determining resources for repetitions ofchannels transmissions to low cost user equipments (UEs).

BACKGROUND

Wireless communication has been one of the most successful innovationsin modern history. Recently, the number of subscribers to wirelesscommunication services exceeded five billion and continues to growquickly. The demand of wireless data traffic is rapidly increasing dueto the growing popularity among consumers and businesses of smart phonesand other mobile data devices, such as tablets, “note pad” computers,net books, eBook readers, and machine type of devices. In order to meetthe high growth in mobile data traffic and support new applications anddeployments, improvements in radio interface efficiency and coverage isof paramount importance.

SUMMARY

This disclosure provides methods and apparatus to determining resourcesfor repetitions, including no repetitions, of channels transmissions tolow cost UEs.

In a first embodiment, a base station is provided. The base stationincludes a transmitter. The transmitter is configured to transmit, in asubframe and in a downlink (DL) system bandwidth that includes an evennumber of M_(RB) ^(DL) DL resource blocks (RBs) indexed in an ascendingorder, a physical DL control channel (PDCCH) or a physical DL sharedchannel (PDSCH) within a sub-band from a set of N_(SB) ^(DL) DLsub-bands (SBs). N_(SB) ^(DL)=└M_(RB) ^(DL)/6┘. Each SB in the setincludes 6 RBs. The 6 RBs of a SB in the set s are not included in anyother SB in the set. the SBs are indexed from 0 to N_(SB) ^(DL)−1 inorder of increasing RB index. (M_(RB) ^(DL)−└M_(RB) ^(DL)/6┘·6)/2 RBswith smallest indexes and (M_(RB) ^(DL)−ℑM_(RB) ^(DL)/6┘·6)/2 RBs withlargest indexes are not included in any SB in the set where └ ┘ is afloor function that rounds a number to an integer that is immediatelysmaller than the number.

In a second embodiment, a UE is provided. The user equipment includes areceiver. The receiver is configured to receive, in a subframe and in aDL system bandwidth that includes an even number of M_(RB) ^(DL) DL RBsindexed in an ascending order, a PDCCH or a PDSCH within a sub-band froma set of N_(SB) ^(DL) DL SBs. N_(SB) ^(DL)=└M_(RB) ^(DL)/6┘. Each SB inthe set includes 6 RBs. The 6 RBs of a SB in the set are not included inany other SB in the set. The SBs are indexed from 0 to N_(SB) ^(DL)−1 inorder of increasing RB index. (M_(RB) ^(DL)−└M_(RB) ^(DL)/6┘·6)/2. RBswith smallest indexes and (M_(RB) ^(DL)−└M_(RB) ^(DL)/6┘·6)/2 RBs withlargest indexes are not included in any SB where └ ┘ is a floor functionthat rounds a number to an integer that is immediately smaller than thenumber.

In a third embodiment, a base station is provided. The base stationincludes a transmitter. The transmitter is configured to transmit anumber of repetitions for a PDSCH conveying a data transport block (TB).The number of repetitions is a multiple of four. The data TB is encodedusing a first redundancy version in first four repetitions.

In a fourth embodiment, a UE is provided. The UE includes a receiver.The receiver is configured to receive a number of repetitions for PDSCHconveying a data transport block (TB). The number of repetitions is amultiple of four. The data TB is encoded using a first redundancyversion in first four repetitions.

Before undertaking the DETAILED DESCRIPTION below, it can beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document. The term “couple” and its derivativesrefer to any direct or indirect communication between two or moreelements, whether or not those elements are in physical contact with oneanother. The terms “transmit,” “receive,” and “communicate,” as well asderivatives thereof, encompass both direct and indirect communication.The terms “include” and “comprise,” as well as derivatives thereof, meaninclusion without limitation. The term “or” is inclusive, meaningand/or. The phrase “associated with,” as well as derivatives thereof,means to include, be included within, interconnect with, contain, becontained within, connect to or with, couple to or with, be communicablewith, cooperate with, interleave, juxtapose, be proximate to, be boundto or with, have, have a property of, have a relationship to or with, orthe like. The term “controller” means any device, system or part thereofthat controls at least one operation. Such a controller can beimplemented in hardware or a combination of hardware and software and/orfirmware. The functionality associated with any particular controllercan be centralized or distributed, whether locally or remotely. Thephrase “at least one of,” when used with a list of items, means thatdifferent combinations of one or more of the listed items can be used,and only one item in the list can be needed. For example, “at least oneof: A, B, and C” includes any of the following combinations: A, B, C, Aand B, A and C, B and C, and A and B and C.

Moreover, various functions described below can be implemented orsupported by one or more computer programs, each of which is formed fromcomputer readable program code and embodied in a computer readablemedium. The terms “application” and “program” refer to one or morecomputer programs, software components, sets of instructions,procedures, functions, objects, classes, instances, related data, or aportion thereof adapted for implementation in a suitable computerreadable program code. The phrase “computer readable program code”includes any type of computer code, including source code, object code,and executable code. The phrase “computer readable medium” includes anytype of medium capable of being accessed by a computer, such as readonly memory (ROM), random access memory (RAM), a hard disk drive, acompact disc (CD), a digital video disc (DVD), or any other type ofmemory. A “non-transitory” computer readable medium excludes wired,wireless, optical, or other communication links that transporttransitory electrical or other signals. A non-transitory computerreadable medium includes media where data can be permanently stored andmedia where data can be stored and later overwritten, such as arewritable optical disc or an erasable memory device.

Definitions for other certain words and phrases are provided throughoutthis disclosure. Those of ordinary skill in the art should understandthat in many when not most instances such definitions apply to prior aswell as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1 illustrates an example wireless communication network accordingto this disclosure;

FIG. 2 illustrates an example UE according to this disclosure;

FIG. 3 illustrates an example enhanced NodeB (eNB) according to thisdisclosure;

FIG. 4 illustrates an example DL SF structure for EPDCCH transmission orPDSCH transmission according to this disclosure;

FIG. 5 illustrates an example UL SF structure for PUSCH transmission orPUCCH transmission according to this disclosure;

FIG. 6 illustrates a transmitter block diagram for a PDSCH in a SFaccording to this disclosure;

FIG. 7 illustrates a receiver block diagram for a PDSCH in a SFaccording to this disclosure;

FIG. 8 illustrates a transmitter block diagram for a PUSCH in a SFaccording to this disclosure;

FIG. 9 illustrates a receiver block diagram for a PUSCH in a SFaccording to this disclosure;

FIG. 10 illustrates an allocation of sub-bands in a DL system BWaccording to this disclosure;

FIG. 11 illustrates an indication of sub-bands for an MPDCCHtransmission according to this disclosure;

FIG. 12 illustrates a determination of sub-bands for repetitions of aPDSCH transmission based on sub-bands for repetitions of an MPDCCHtransmission according to this disclosure;

FIG. 13 illustrates RBs for repetitions of a PUCCH transmissionaccording to a first CE level and according to a second CE levelaccording to this disclosure;

FIG. 14 illustrates a method for a LC/CE UE operating with CE todetermine a PUCCH resource for a transmission of HARQ-ACK informationaccording to this disclosure;

FIG. 15 illustrates multiplexing for repetitions of PUSCH transmissions,with and without frequency hopping, over 2 RBs according to thisdisclosure;

FIG. 16 illustrates a first realization for a use of RVs for repetitionsof a PDSCH transmission in a sub-band and in different sub-bandsaccording to this disclosure;

FIG. 17 illustrates a first realization for a use of RVs for repetitionsof a PDSCH transmission in a sub-band and in different sub-bandsaccording to this disclosure;

FIG. 18 illustrates a use of hopping to determine sub-bands for a PDSCHtransmission according to this disclosure; and

FIG. 19 illustrates a use of a pseudorandom subset of SFs per frame forrepetitions of a channel transmission according to this disclosure.

DETAILED DESCRIPTION

FIGS. 1 through 19, discussed below, and the various embodiments used todescribe the principles of the present disclosure in this patentdocument are by way of illustration only and should not be construed inany way to limit the scope of the disclosure. Those skilled in the artwill understand that the principles of the present disclosure can beimplemented in any suitably arranged wireless communication system.

The following documents and standards descriptions are herebyincorporated by reference into the present disclosure as when fully setforth herein: 3GPP TS 36.211 v12.4.0, “E-UTRA, Physical channels andmodulation” (REF 1); 3GPP TS 36.212 v12.3.0, “E-UTRA, Multiplexing andChannel coding” (REF 2); 3GPP TS 36.213 v12.4.0, “E-UTRA, Physical LayerProcedures” (REF 3); 3GPP TS 36.321 v12.4.0, “E-UTRA, Medium AccessControl (MAC) protocol specification” (REF 4); and 3GPP TS 36.331v12.4.0, “E-UTRA, Radio Resource Control (RRC) Protocol Specification”(REF 5).

This disclosure relates to determining resources and to transmitting andreceiving repetitions, including no repetitions, for transmissions ofchannels to or from UEs. A wireless communication network includes a DLthat conveys signals from transmission points, such as base stations orenhanced eNBs, to UEs. The wireless communication network also includesan UL that conveys signals from UEs to reception points, such as eNBs.

FIG. 1 illustrates an example wireless network 100 according to thisdisclosure. The embodiment of the wireless network 100 shown in FIG. 1is for illustration only. Other embodiments of the wireless network 100could be used without departing from the scope of this disclosure.

As shown in FIG. 1, the wireless network 100 includes an eNB 101, an eNB102, and an eNB 103. The eNB 101 communicates with the eNB 102 and theeNB 103. The eNB 101 also communicates with at least one InternetProtocol (IP) network 130, such as the Internet, a proprietary IPnetwork, or other data network.

Depending on the network type, other well-known terms can be usedinstead of “NodeB” or “eNB,” such as “base station” or “access point.”For the sake of convenience, the terms “NodeB” and “eNB” are used inthis patent document to refer to network infrastructure components thatprovide wireless access to remote terminals. Also, depending on thenetwork type, other well-known terms can be used instead of “userequipment” or “UE,” such as “mobile station,” “subscriber station,”“remote terminal,” “wireless terminal,” or “user device.” A UE, can befixed or mobile and can be a cellular phone, a personal computer device,and the like. For the sake of convenience, the terms “user equipment”and “UE” are used in this patent document to refer to remote wirelessequipment that wirelessly accesses an eNB, whether the UE is a mobiledevice (such as a mobile telephone or smart-phone) or is normallyconsidered a stationary device (such as a desktop computer or vendingmachine).

The eNB 102 provides wireless broadband access to the network 130 for afirst plurality of UEs within a coverage area 120 of the eNB 102. Thefirst plurality of UEs includes a UE 111, which can be located in asmall business (SBS); a UE 112, which can be located in an enterprise(E); a UE 113, which can be located in a WiFi hotspot (HS); a UE 114,which can be located in a first residence (R); a UE 115, which can belocated in a second residence (R); and a UE 116, which can be a mobiledevice (M) like a cell phone, a wireless laptop, a wireless PDA, or thelike. The eNB 103 provides wireless broadband access to the network 130for a second plurality of UEs within a coverage area 125 of the eNB 103.The second plurality of UEs includes the UE 115 and the UE 116. In someembodiments, one or more of the eNBs 101-103 can communicate with eachother and with the UEs 111-116 using 5G, LTE, LTE-A, WiMAX, or otheradvanced wireless communication techniques.

Dotted lines show the approximate extents of the coverage areas 120 and125, which are shown as approximately circular for the purposes ofillustration and explanation only. It should be clearly understood thatthe coverage areas associated with eNBs, such as the coverage areas 120and 125, can have other shapes, including irregular shapes, dependingupon the configuration of the eNBs and variations in the radioenvironment associated with natural and man-made obstructions.

As described in more detail below, various components of the network100, such as the eNBs 101-103, support the adaptation of communicationdirection in the network 100, and can transmit and receive repetitionsfor transmissions of channels in order to communicate with one or moreof UEs 111-116. In addition, one or more of UEs 111-116 are configuredto support the adaptation of communication direction in the network 100,and to transmit and receive repetitions of channels transmissions forcommunication between one or more of eNBs 101-103 with one or more ofUEs 111-116.

Although FIG. 1 illustrates one example of a wireless network 100,various changes can be made to FIG. 1. For example, the wireless network100 could include any number of eNBs and any number of UEs in anysuitable arrangement. Also, the eNB 101 could communicate directly withany number of UEs and provide those UEs with wireless broadband accessto the network 130. Similarly, each eNB 102-103 could communicatedirectly with the network 130 and provide UEs with direct wirelessbroadband access to the network 130. Further, the eNB 101, 102, and/or103 could provide access to other or additional external networks, suchas external telephone networks or other types of data networks.

FIG. 2 illustrates an example UE 114 according to this disclosure. Theembodiment of the UE 114 shown in FIG. 2 is for illustration only, andthe other UEs in FIG. 1 could have the same or similar configuration.However, UEs come in a wide variety of configurations, and FIG. 2 doesnot limit the scope of this disclosure to any particular implementationof a UE.

As shown in FIG. 2, the UE 114 includes an antenna 205, a radiofrequency (RF) transceiver 210, transmit (TX) processing circuitry 215,a microphone 220, and receive (RX) processing circuitry 225. The UE 114also includes a speaker 230, a processor 240, an input/output (I/O)interface (IF) 245, a keypad 250, a display 255, and a memory 260. Thememory 260 includes an operating system (OS) program 261 and one or moreapplications 262.

The RF transceiver 210 receives, from the antenna 205, an incoming RFsignal transmitted by an eNB or another UE. The RF transceiver 210down-converts the incoming RF signal to generate an intermediatefrequency (IF) or baseband signal. The IF or baseband signal is sent tothe RX processing circuitry 225, which generates a processed basebandsignal by filtering, decoding, and/or digitizing the baseband or IFsignal. The RX processing circuitry 225 transmits the processed basebandsignal to the speaker 230 (such as for voice data) or to the processor240 for further processing (such as for web browsing data).

The TX processing circuitry 215 receives analog or digital voice datafrom the microphone 220 or other outgoing baseband data (such as webdata, e-mail, or interactive video game data) from the processor 240.The TX processing circuitry 215 encodes, multiplexes, and/or digitizesthe outgoing baseband data to generate a processed baseband or IFsignal. The RF transceiver 210 receives the outgoing processed basebandor IF signal from the TX processing circuitry 215 and up-converts thebaseband or IF signal to an RF signal that is transmitted via theantenna 205.

The processor 240 can include one or more processors or other processingdevices and can execute the OS program 261 stored in the memory 260 inorder to control the overall operation of the UE 114. For example, theprocessor 240 could control the reception of forward channel signals andthe transmission of reverse channel signals by the RF transceiver 210,the RX processing circuitry 225, and the TX processing circuitry 215 inaccordance with well-known principles. In some embodiments, theprocessor 240 includes at least one microprocessor or microcontroller.

The processor 240 is also capable of executing other processes andprograms resident in the memory 260. The processor 240 can move datainto or out of the memory 260 as required by an executing process. Insome embodiments, the processor 240 is configured to execute theapplications 262 based on the OS program 261 or in response to signalsreceived from eNBs, other UEs, or an operator. The processor 240 is alsocoupled to the I/O interface 245, which provides the UE 114 with theability to connect to other devices such as laptop computers andhandheld computers. The I/O interface 245 is the communication pathbetween these accessories and the processor 240.

The processor 240 is also coupled to the input 250 (e.g., touchscreen,keypad, etc.) and the display 255. The operator of the UE 114 can usethe input 250 to enter data into the UE 114. The display 255 can be aliquid crystal display or other display capable of rendering text and/orat least limited graphics, such as from web sites. The display 255 couldalso represent a touch-screen.

The memory 260 is coupled to the main 240. Part of the memory 260 couldinclude a broadcast signaling memory (RAM), and another part of thememory 260 could include a Flash memory or other read-only memory (ROM).

As described in more detail below, the transmit and receive paths of theUE 114 support determining resources for repetitions, including norepetitions, and transmitting and receiving repetitions fortransmissions of channels in a normal coverage mode (no repetitions) orin an enhanced coverage mode. In certain embodiments, the TX processingcircuitry 215 and RX processing circuitry 225 include processingcircuitry configured to determine resources for repetitions of channelstransmissions in a normal coverage mode (no repetitions) or in anenhanced coverage mode. In certain embodiments, the processor 240 isconfigured to control the RF transceivers 210, the TX processingcircuitry 215, or the RX processing circuitry 225, or a combinationthereof, to determine resources for repetitions, including norepetitions, of transmissions in a normal mode or in an enhancedcoverage mode.

Although FIG. 2 illustrates one example of UE 114, various changes canbe made to FIG. 2. For example, various components in FIG. 2 could becombined, further subdivided, or omitted and additional components couldbe added according to particular needs. As a particular example, theprocessor 240 could be divided into multiple processors, such as one ormore central processing units (CPUs) and one or more graphics processingunits (GPUs). Also, while FIG. 2 illustrates the UE 114 configured as amobile telephone or smart-phone, UEs could be configured to operate asother types of mobile or stationary devices. In addition, variouscomponents in FIG. 2 could be replicated, such as when different RFcomponents are used to communicate with the eNBs 101-103 and with otherUEs.

FIG. 3 illustrates an example eNB 102 according to this disclosure. Theembodiment of the eNB 102 shown in FIG. 3 is for illustration only, andother eNBs of FIG. 1 could have the same or similar configuration.However, eNBs come in a wide variety of configurations, and FIG. 3 doesnot limit the scope of this disclosure to any particular implementationof an eNB.

As shown in FIG. 3, the eNB 102 includes multiple antennas 305 a-305 n,multiple RF transceivers 310 a-310 n, transmit (TX) processing circuitry315, and receive (RX) processing circuitry 320. The eNB 102 alsoincludes a controller/processor 325, a memory 330, and a backhaul ornetwork interface 335.

The RF transceivers 310 a-310 n receive, from the antennas 305 a-305 n,incoming RF signals, such as signals transmitted by UEs or other eNBs.The RF transceivers 310 a-310 n down-convert the incoming RF signals togenerate IF or baseband signals. The IF or baseband signals are sent tothe RX processing circuitry 320, which generates processed basebandsignals by filtering, decoding, and/or digitizing the baseband or IFsignals. The RX processing circuitry 320 transmits the processedbaseband signals to the controller/processor 325 for further processing.

The TX processing circuitry 315 receives analog or digital data (such asvoice data, web data, e-mail, or interactive video game data) from thecontroller/processor 325. The TX processing circuitry 315 encodes,multiplexes, and/or digitizes the outgoing baseband data to generateprocessed baseband or IF signals. The RF transceivers 310 a-310 nreceive the outgoing processed baseband or IF signals from the TXprocessing circuitry 315 and up-converts the baseband or IF signals toRF signals that are transmitted via the antennas 305 a-305 n.

The controller/processor 325 can include one or more processors or otherprocessing devices that control the overall operation of the eNB 102.For example, the controller/processor 325 could control the reception offorward channel signals and the transmission of reverse channel signalsby the RF transceivers 310 a-310 n, the RX processing circuitry 320, andthe TX processing circuitry 315 in accordance with well-knownprinciples. The controller/processor 325 could support additionalfunctions as well, such as more advanced wireless communicationfunctions. For instance, the controller/processor 325 could support beamforming or directional routing operations in which outgoing signals frommultiple antennas 305 a-305 n are weighted differently to effectivelysteer the outgoing signals in a desired direction. Any of a wide varietyof other functions could be supported in the eNB 102 by thecontroller/processor 325. In some embodiments, the controller/processor325 includes at least one microprocessor or microcontroller.

The controller/processor 325 is also capable of executing programs andother processes resident in the memory 330, such as a basic OS. Thecontroller/processor 325 can move data into or out of the memory 330 asrequired by an executing process.

The controller/processor 325 is also coupled to the backhaul or networkinterface 335. The backhaul or network interface 335 allows the eNB 102to communicate with other devices or systems over a backhaul connectionor over a network. The interface 335 could support communications overany suitable wired or wireless connection(s). For example, when the eNB102 is implemented as part of a cellular communication system (such asone supporting 5G, LTE, or LTE-A), the interface 335 could allow the eNB102 to communicate with other eNBs over a wired or wireless backhaulconnection. When the eNB 102 is implemented as an access point, theinterface 335 could allow the eNB 102 to communicate over a wired orwireless local area network or over a wired or wireless connection to alarger network (such as the Internet). The interface 335 includes anysuitable structure supporting communications over a wired or wirelessconnection, such as an Ethernet or RF transceiver.

The memory 330 is coupled to the controller/processor 325. Part of thememory 330 could include a RAM, and another part of the memory 330 couldinclude a Flash memory or other ROM.

As described in more detail below, the transmit and receive paths of theeNB 102 support determination of resources for repetitions, including norepetitions, and transmission and reception of repetitions for channelstransmissions to or from UEs in a normal mode or in an enhanced coveragemode. In certain embodiments, the TX processing circuitry 315 and RXprocessing circuitry 320 include processing circuitry configured tosupport determination of resources for repetitions of channelstransmissions to low cost user equipments in a normal mode or in anenhanced coverage mode. In certain embodiments, the processor 240 isconfigured to control the RF transceivers 310 a-310 n, TX processingcircuitry 315 or RX processing circuitry 320, or a combination thereof,to support determination of resources for repetitions of channelstransmissions to low cost user equipments in a normal mode or in anenhanced coverage mode.

Although FIG. 3 illustrates one example of an eNB 102, various changescan be made to FIG. 3. For example, the eNB 102 could include any numberof each component shown in FIG. 3. As a particular example, an accesspoint could include a number of interfaces 335, and thecontroller/processor 325 could support routing functions to route databetween different network addresses. As another particular example,while shown as including a single instance of TX processing circuitry315 and a single instance of RX processing circuitry 320, the eNB 102could include multiple instances of each (such as one per RFtransceiver).

A transmission time interval (TTI) for DL signaling or UL signaling isreferred to as a subframe (SF) and includes two slots. A unit of ten SFsis referred to as a frame. A bandwidth (BW) unit is referred to as aresource block (RB), one RB over one slot is referred to as a physicalRB (PRB) and one RB over one SF is referred to as a PRB pair.

In some wireless networks, DL signals include data signals conveyinginformation content, control signals conveying DL control information(DCI), and reference signals (RS) that are also known as pilot signals.The eNB 102 transmits data information through respective physical DLshared channels (PDSCHs). The eNB 102 also transmits DCI throughrespective physical DL control channels (PDCCHs) or enhanced PDCCH(EPDCCH). The eNB 102 can transmit one or more of multiple types of RSincluding a UE-common RS (CRS), a channel state information RS (CSI-RS),and a demodulation RS (DMRS)—see also REF 1. The eNB 102 transmits a CRSover a DL system BW and the CRS can be used by UEs to demodulate data orcontrol signals or to perform measurements. To reduce CRS overhead, theeNB 102 can transmit a CSI-RS with a smaller density in the time and/orfrequency domain than a CRS. UE 114 can determine CSI-RS transmissionparameters, when applicable, through higher layer signaling from eNB102. DMRS is transmitted only in the BW of a respective PDSCH or PDCCHand UE 114 can use the DMRS to demodulate information in the PDSCH orthe PDCCH. DL signals also include transmission of a logical channelthat carries system control information is referred to as broadcastcontrol channel (BCCH). A BCCH is mapped to either a transport channelreferred to as a broadcast channel (BCH) or to a DL shared channel(DL-SCH). Most UE-common system information (SI) is included indifferent SI blocks (SIBs) that are transmitted using DL-SCH.

FIG. 4 illustrates an example DL SF structure for EPDCCH transmission orPDSCH transmission according to this disclosure. The embodiment of theDL SF structure shown in FIG. 4 is for illustration only. Otherembodiments could be used without departing from the scope of thepresent invention.

A DL SF 410 includes two slots 420 and a total of N_(symb) ^(DL) symbolsfor transmitting of data information and DCI. The first M_(symb) ^(DL)SF symbols are used to transmit PDCCHs and other control channels (notshown) 430. The remaining N_(symb) ^(DL)−M_(symb) ^(DL) SF symbols areprimarily used to transmit PDSCHs such as 440 and 442, or EPDCCHs suchas 450 and 452. A transmission BW consists of frequency resource unitsreferred to as resource blocks (RBs). Each RB consists of N_(sc) ^(RB)sub-carriers, or resource elements (REs), such as 12 REs. A unit of oneRB over one SF is referred to as a physical RB (PRB). A UE can beallocated M_(PDSCH) RBs for a total of M_(sc) ^(PDSCH)=M_(PDSCH)·N_(sc)^(RB) REs for the PDSCH transmission BW. An EPDCCH transmission can bein one RB or in multiple of RBs.

In some wireless networks, UL signals include data signals conveyingdata information, control signals conveying UL control information(UCI), and UL RS. UE 114 transmits data information or UCI through arespective physical UL shared channel (PUSCH) or a physical UL controlchannel (PUCCH). When UE 114 needs to transmit data information and UCIin a same SF, UE 114 can multiplex both in a PUSCH. UCI includes HARQacknowledgement (HARQ-ACK) information indicating correct (ACK) orincorrect (NACK) detection for data transport block (TB) in a PDSCH, orabsence of a PDCCH detection (DTX), scheduling request (SR) indicatingwhether UE 114 has data in the UE's buffer, and channel stateinformation (CSI) enabling eNB 102 to perform link adaptation for PDSCHtransmissions to UE 114. The HARQ-ACK information is also transmitted byUE 114 in response to a detection of a PDCCH indicating a release ofsemi-persistently scheduled (SPS) PDSCH (see also REF 3). For brevity,this is not explicitly mentioned in the following descriptions.

UL RS includes DMRS and sounding RS (SRS). UE 114 transmits DMRS only ina BW of a respective PUSCH or PUCCH and eNB 102 can use a DMRS todemodulate data information or UCI. A DMRS is transmitted using aZadoff-Chu (ZC) sequence having a cyclic shift (CS) and an orthogonalcovering code (OCC) that eNB 102 can inform to UE 114 through arespective UL DCI format (see also REF 2) or configure by higher layersignaling such as radio resource control (RRC) signaling. UE 114transmits SRS to provide eNB 102 with an UL CSI. The SRS transmissioncan be periodic (P-SRS), at predetermined SFs with parameters configuredto UE 114 from eNB 102 by higher layer signaling, or aperiodic (A-SRS)as triggered by a DCI format scheduling PUSCH or PDSCH (DL DCI format)(see also REF 2 and REF 3).

FIG. 5 illustrates an example UL SF structure for PUSCH transmission orPUCCH transmission according to this disclosure. The embodiment of theUL SF structure shown in FIG. 5 is for illustration only. Otherembodiments could be used without departing from the scope of thepresent disclosure.

In the example shown in FIG. 5, an UL SF 510 includes two slots 520.Each slot 520 includes N_(symb) ^(UL) symbols 530 for transmitting datainformation, UCI, DMRS, or SRS. Each RB includes N_(sc) ^(RB) REs. UE114 is allocated N_(RB) RBs 540 for a total of N_(RB)·N_(sc) ^(RB) REsfor a transmission BW. For a PUCCH, N_(RB)=1. A last SF symbol can beused to multiplex SRS transmissions 550 from one or more UEs. A numberof SF symbols that are available for data/UCI/DMRS transmission isN_(symb)=2·(N_(symb) ^(UL)−1)N_(SRS), where N_(SRS)=1 when a last SFsymbol is used to transmit SRS and N_(SRS)=0 otherwise.

FIG. 6 illustrates a transmitter block diagram for a PDSCH in a SFaccording to this disclosure. The embodiment of the PDSCH transmitterblock diagram shown in FIG. 6 is for illustration only. Otherembodiments could be used without departing from the scope of thepresent invention.

Information bits 610 are encoded by encoder 620, such as a turboencoder, and modulated by modulator 630, for example using quadraturephase shift keying (QPSK) modulation. A serial-to-parallel (S/P)converter 640 generates M modulation symbols that are subsequentlyprovided to a mapper 650 to be mapped to REs selected by a transmissionBW selection unit 655 for an assigned PDSCH transmission BW, unit 660applies an inverse fast Fourier transform (IFFT), the output is thenserialized by a parallel-to-serial (P/S) converter 670 to create a timedomain signal, filtering is applied by filter 680, and a signaltransmitted 690. Additional functionalities, such as data scrambling,cyclic prefix insertion, time windowing, interleaving, and others arewell known in the art and are not shown for brevity.

FIG. 7 illustrates a receiver block diagram for a PDSCH in a SFaccording to this disclosure. The embodiment of the PDSCH receiver blockdiagram shown in FIG. 7 is for illustration only. Other embodimentscould be used without departing from the scope of the present invention.

A received signal 710 is filtered by filter 720, REs 730 for an assignedreception BW are selected by BW selector 735, unit 740 applies a fastFourier transform (FFT), and an output is serialized by aparallel-to-serial converter 750. Subsequently, a demodulator 760coherently demodulates data symbols by applying a channel estimateobtained from a DMRS or a CRS (not shown), and a decoder 770, such as aturbo decoder, decodes the demodulated data to provide an estimate ofthe information data bits 780. Additional functionalities such astime-windowing, cyclic prefix removal, de-scrambling, channelestimation, and de-interleaving are not shown for brevity.

FIG. 8 illustrates a transmitter block diagram for a PUSCH in a SFaccording to this disclosure. The embodiment of the transmitter blockdiagram shown in FIG. 8 is for illustration only. Other embodimentscould be used without departing from the scope of the presentdisclosure.

Information data bits 810 are encoded by encoder 820, such as a turboencoder, and modulated by modulator 830. A discrete Fourier transform(DFT) filter 840 applies a DFT on the modulated data bits, REs 850corresponding to an assigned PUSCH transmission BW are selected bytransmission BW selection unit 855, filter 860 applies an IFFT and,after a cyclic prefix insertion (not shown), filtering is applied byfilter 870 and a signal transmitted 880.

FIG. 9 illustrates a receiver block diagram for a PUSCH in a SFaccording to this disclosure. The embodiment of the receiver blockdiagram shown in FIG. 6 is for illustration only. Other embodimentscould be used without departing from the scope of the presentdisclosure.

A received signal 910 is filtered by filter 920. Subsequently, after acyclic prefix is removed (not shown), filter 930 applies a FFT, REs 940corresponding to an assigned PUSCH reception BW are selected by areception BW selector 945, filter 950 applies an inverse DFT (IDFT), ademodulator 960 coherently demodulates data symbols by applying achannel estimate obtained from a DMRS (not shown), a decoder 970, suchas a turbo decoder, decodes the demodulated data to provide an estimateof the information data bits 980.

Machine type communications (MTC) or internet of things (IoT) refers tocommunications of automated devices in a network. MTC through cellularnetworks is emerging as a significant opportunity for new applicationsin a networked world where devices communicate with humans and with eachother. Compared to typical human communication, MTC typically hasrelaxed latency and quality of service (QoS) requirements and often doesnot require mobility support. MTC can be used for a wide variety ofapplications in different sectors including healthcare, such asmonitors, industrial, such as safety and security, energy, such asmeters and turbines, transport, such as fleet management and tolls, andconsumer and home, such as appliances and power systems.

An important requirement for commercial success of MTC is for respectiveUEs to have low power consumption and significantly lower cost than forUEs serving human communications. Cost reduction for low cost UEs (LCUEs), relative to UEs serving human communication, can be achieved,among other simplifications, by constraining a transmission BW and areception BW to a small value, such as 6 RBs, of an UL system BW or a DLsystem BW, respectively, by reducing a maximum size of a data TB a UEtransmit or receive, or by implementing one receiver antenna instead oftwo receiver antennas.

LC UEs can be installed in basements of residential buildings or,generally, in locations where a LC UE experiences a large path-loss lossand poor coverage due to a low signal to noise and interference ratio(SINR). LC UE design selections of one receiver antenna and reducedmaximum power amplifier gain can also result to coverage loss even whena LC UE does not experience a large path-loss. Due to such reasons, a LCUE can require operation with enhanced coverage (EC). In extreme poorcoverage scenarios, LC UEs can have characteristics such as very lowdata rate, greater delay tolerance, and limited mobility. Not all LC UEsrequire coverage enhancement (CE) (LC/CE UEs) or a same amount of CE. Inaddition, in different deployment scenarios, a required CE level can bedifferent for different eNBs, for example depending on a eNBtransmission power or on an associated cell size or on a number of eNBreceiver antennas, as well as for different LC/CE UEs, for exampledepending on a location of a LC/CE UE.

LC/CE UE 114 or eNB 102 can support CE by repeating transmissions ofchannels either in a time domain or in a frequency domain. LC/CE UE 114operating with CE can be configured by eNB 102 with a CE levelcorresponding to a number of SFs for a transmission or reception of arespective channel (number of repetitions for a transmission of achannel). For example, LC/CE UE 114 can be configured by eNB 102 a firstnumber of repetitions for reception of a PDSCH transmission, a secondnumber of repetitions for a PUSCH transmission, and so on.

A DL control channel for LC/CE UE 114 is assumed to be based on theEPDCCH structure and will be referred to as MPDCCH. In order to minimizea number of repetitions that LC/CE UE 114 needs to receive a PDSCH or anMPDCCH, respective transmissions can be over all RBs where LC/CE UE 114can receive in a SF, such as in a sub-band of 6 contiguous RBs, as eNB102 is assumed to not be power limited. Conversely, as LC/CE UE 114 usesa maximum transmission power when configured to transmit an UL channelwith repetitions, in order to maximize a power spectral density, the ULchannel transmission from LC/CE UE 114 can be limited to 1 RB or lessthan 1 RB per SF.

Transmissions of physical channels with repetitions consume additionalresources and result to lower spectral efficiency and larger LC/CE UEpower consumption. It is therefore beneficial to enable mechanisms thatprovide improved reception reliability. Such mechanisms include improvedreliability of a channel estimate used for coherent demodulation of dataor control symbols, frequency diversity through frequency hopping whensub-band CSI is either not available or not reliable, and codingdiversity through a use of incremental redundancy (IR) with differentredundancy versions (RVs) among repetitions of a data channeltransmission (see also REF 2 and REF 3).

Certain embodiments of this disclosure provide a determination ofsub-bands in a DL system BW or of sub-bands in an UL system BW forcommunication between eNB 102 and LC/CE UE 114. Certain embodiments ofthis disclosure also provide mechanisms to signal sub-bands or RBs forMPDCCH or PDSCH transmissions from eNB 102 to LC/CE UE 114 and for PUSCHor PUCCH transmissions from LC/CE UE 114 to eNB 102. Additionally,certain embodiments of this disclosure provide mechanisms to enablecoding diversity for transmissions with repetitions from eNB 102 toLC/CE UE 114 or from LC/CE UE 114 to eNB 102 while improving an accuracyof a channel estimate and simplifying a receiver implementation.Further, certain embodiments of this disclosure provide randomization ofPDSCH transmissions that are not scheduled by an MPDCCH in order tomitigate interference among such PDSCH transmissions from neighboringeNBs.

The following embodiments are not limited to LC/CE UEs and can beapplicable to any type of UEs requiring coverage enhancements. Thisincludes UEs that can receive over the entire DL system BW or transmitover the entire UL system BW at a given time instance (referred to asconventional UEs). In the following, for brevity, FDD is considered asthe duplex method for both DL and UL signaling but the embodiments ofthe disclosure are also directly applicable to TDD. MPDCCH or PDSCHtransmission to a LC/CE UE and PUCCH or PUSCH transmissions from a LC/CEUE are assumed to be with repetitions, including no repetitions, in anumber of SFs.

Various embodiments of the disclosure provide for determination andallocation of sub-bands in a DL system BW or in an UL system BW.

A first step in determining a frequency hopping pattern for repetitionsof an MPDCCH or a PDSCH transmission from eNB 102 to LC/CE UE 114, orfor repetitions of a PUCCH or a PUSCH transmission from LC/CE UE 114 toeNB 102, is a determination of respective sub-bands in a DL system BW ora determination of respective sub-bands or RBs in an UL system BW. Asthis determination can be same in the DL and the UL, only the DL issubsequently referenced for brevity.

A number of available sub-bands in a DL system BW of M_(RB) ^(DL) RBs isequal to └M_(RB) ^(DL)/6┘ where a sub-band is assumed to include 6consecutive RBs and └ ┘ is the ‘floor’ function that rounds a number toits immediately smaller integer.

In a first approach, RBs allocated to sub-bands are counted either fromthe lowest indexed RB or from the highest indexed RB. A number of M_(RB)^(DL)−└M_(RB) ^(DL)/6┘·6 highest indexed or lowest indexed RBs,respectively, are not included in any sub-band.

As eNB 102 can boost, when possible, a transmission power to LC/CE UE114 that is configured to receive repetitions of an MPDCCH or a PDSCHtransmission, in order to reduce a number of repetitions required forLC/CE UE 114 to detect a respective MPDCCH or PDSCH with a target blockerror rate (BLER), it can be beneficial to place the sub-bands in theinterior of the DL system BW in order to reduce the effect ofout-of-band emissions. Then, in a second approach, the sub-bands excludeM_(RB) ^(DL)−└M_(RB) ^(DL)/6┘·6 RBs where the indexing of excluded RBsalternates between the lowest indexed ones and the highest indexed ones.For example, for M_(RB) ^(DL)=50 RBs, there can be 8 non-overlappingsub-bands, each of 6 RBs, over 48 RBs and the 2 excluded RBs are thelowest indexed one and the highest indexed one; that is, (M_(RB)^(DL)−└M_(RB) ^(DL)/6┘·6)/2 RBs with the lowest indexes and (M_(RB)^(DL)−└M_(RB) ^(DL)/6┘·6)/2 RBs with the highest indexes are excluded.

FIG. 10 illustrates an allocation of sub-bands in a DL system BWaccording to this disclosure.

A DL system BW includes M_(RB) ^(DL) RBs. A number of sub-bands equal to└M_(RB) ^(DL)/6┘ is defined where each sub-band includes 6 consecutiveRBs and different sub-bands do not include any overlapping RBs. Thereare M_(RB) ^(DL)−└M_(RB) ^(DL)/6┘·6 =2 RBs that are not allocated to anysub-band. The 2 RBs are the RB with the lowest index 1010 and the RBwith the highest index 1015 in the DL system BW. The RBs of the DLsystem BW that exclude the first RB and the last RB are allocated to the└M_(RB) ^(DL)/6┘ sub-bands where all sub-bands include mutuallydifferent RBs and where the first sub-band 1020 includes the 6 lowerindexed RBs (other than the first RB of the DL system BW) and the lastsub-band 1030 includes the 6 highest indexed RB (other than the last RBof the DL system BW). Therefore, there is a total of N_(SB)^(DL)=└M_(RB) ^(DL)/6┘ sub-bands in a DL system BW, numbered as n_(SB)^(DL)=0, . . . , N_(SB) ^(DL)−1 in order of increasing RB number, andsub-band n_(SB) ^(DL) includes the 6 RBs 6·n_(SB) ^(DL)+n₀+n where n=0,1, . . . , 5 and, for even values of M_(RB) ^(DL) and N_(SB) ^(DL),n₀=(M^(DL) _(RB)−6·N_(SB) ^(DL))/2.

Configuration of Sub-Bands for MPDCCH Transmission

In a first approach, a configuration of sub-bands for R^(M-PDCCH)repetitions of an MPDCCH transmission to LC/CE UE 114 can be part of aRRC connection setup between LC/CE UE 114 and eNB 102 after LC/CE UE 114has established initial access with eNB 102 using a random accessprocess. The RRC connection setup can be provided by “message 4” of therandom access process or by a subsequent PDSCH transmission. In additionto the configuration of sub-bands for repetitions of an MPDCCHtransmission, a first sub-band for a first number of repetitions inrespective SFs, R_(SB) ^(M-PDCCH), assuming frequency hopping of anMPDCCH transmission across the configured sub-bands, needs to beindicated by eNB 102 to LC/CE UE 114 in order to allow MPDCCHtransmissions to different LC/CE UEs in different sub-bands during sameSFs. Therefore, eNB 102 indicates to LC/CE UE 114 the sub-bands forrepetitions of an MPDCCH transmission from a total of └M_(RB) ^(DL)/6┘sub-bands and a sub-band for a first number of repetitions, from theR^(M-PDCCH) repetitions, of an MPDCCH transmission.

In another example, eNB 102 configures to LC/CE UE 114 the sub-bands forMPDCCH repetitions using a bit-map having a size equal to a number ofsub-bands in the DL system BW wherein a binary ‘1’, for example, canindicate that a sub-band is used for a repetition of an MPDCCHtransmission. For example, for a DL system BW of M_(RB) ^(DL)=50 RBs,there can be N_(SB) ^(DL)=└M_(RB) ^(DL)/6┘=8 sub-bands and the bit-mapsize is 8 bits while for a DL system BW of M_(RB) ^(DL)=100 RBs, therecan be N_(SB) ^(DL)=└M_(RB) ^(DL)/6┘=16 sub-bands and the bit-map sizewhen 16 bits.

In yet another example, when a number of sub-bands N_(SB) ^(M-PDCCH)used for repetitions of an MPDCCH transmission is predetermined, eitherin the system operation or by configuration, such as for example N_(SB)^(M-PDCCH)=2 or N_(SB) ^(M-PDCCH)=4 sub-bands, it is possible to reducea number of bits required for indicating the sub-bands used forrepetitions of an MPDCCH transmission by using a combinatorial index r(see also REF 3).

The combinatorial index r corresponds to the sub-band index

{k_(i)}_(i = 0)^(N_(SB)^(M − PDCCH) − 1), (1 ≤ k_(i) ≤ N_(SB)^(DL), k_(i) < k_(i + 1))and is given by equation

$r = {\sum\limits_{i = 0}^{N_{SB}^{M - {PDCCH}} - 1}\left\langle \begin{matrix}{N_{SB}^{DL} - k_{i}} \\{N_{SB}^{M - {PDCCH}} - i}\end{matrix} \right\rangle}$where

$\left\langle \begin{matrix}x \\y\end{matrix} \right\rangle = \left\{ \begin{matrix}\begin{pmatrix}x \\y\end{pmatrix} & {x \geq y} \\0 & {x < y}\end{matrix} \right.$is the extended binomial coefficient, resulting in unique label

$r \in {\left\{ {0,\ldots\mspace{14mu},{\begin{pmatrix}N_{SB}^{DL} \\N_{SB}^{M - {PDCCH}}\end{pmatrix} - 1}} \right\}.}$The number of bits needed to indicate the index r is

$\left\lceil {\log_{2}\begin{pmatrix}N_{SB}^{DL} \\N_{SB}^{M - {PDCCH}}\end{pmatrix}} \right\rceil$where ┌ ┐ is the ‘ceiling’ function that rounds a number to itsimmediately larger integer. For example, for N_(SB) ^(DL)=8 and N_(SB)^(M-PDCCH)=2 the number of bits is 5, while for N_(SB) ^(DL)=16 andN_(SB) ^(M-PDCCH)=2 the number of bits is 7. When N_(SB) ^(M-PDCCH) isnot predetermined in the system operation but also needs to be indicatedamong S_(M-PDCCH) possible values, ┌log₂ S_(M-PDCCH)┐ additional bitsare needed. For example, when possible values for S_(SB) ^(M-PDCCH) are2 and 4, one additional bit is needed.

A number of bits required to indicate N_(SB) ^(M-PDCCH) sub bands forrepetitions of an MPDCCH transmission, using either the bit-map or thecombinatorial index, can be reduced when the N_(SB) ^(M-PDCCH) sub-bandsare restricted to have a predefined symmetry that is determined by anoffset relative to a first sub-band that eNB 102 configures to UE 114.The offset can be predefined or configured by eNB 102 to LC/CE UE 114and is common for all LC/CE UEs. For example, for N_(SB) ^(M-PDCCH)=2and a predetermined offset, when a sub-band with index k₁, 0≤k₁<└N_(SB)^(DL)/2┘, is configured to UE 114 by eNB 102, the sub-band with indexk₁+└N_(SB) ^(DL)/2┘ (offset of └N_(SB) ^(DL)/2┘ sub-bands) or thesub-band with index N_(SB) ^(DL)−k₁−1 (mirrored sub-band from the otherside of the DL BW) is also configured as a result of the predefinedsymmetry. For example, for N_(SB) ^(M-PDCCH)=2 and an offset O_(SB)^(DL) configured by eNB 102 to LC/CE UE 114 through a SIB, the sub-bandwith index k₂=k₁+O_(SB) ^(DL) (modulo N_(SB) ^(DL)) is also configuredby eNB 102 to UE 114 as a result of the configuration of the firstsub-band with index k₁ and the offset O_(SB) ^(DL).

FIG. 11 illustrates an indication of sub-bands for an MPDCCHtransmission according to this disclosure.

A DL system BW includes N_(SB) ^(DL)=8 sub-bands and eNB 102 configuresLC/CE UE 114 with N_(SB) ^(M-PDCCH)=2 sub-bands for repetitions of anMPDCCH transmission. LC/CE UE 114 is also configured by eNB 102 a firstsub-band with index k₁=1 1110 among the first └N_(SB) ^(DL)/2┘=4sub-bands. LC/CE UE 114 derives a second sub-band 1120 with index k₂=6either based on a predefined symmetry for the second sub-band index ofN_(SB) ^(DL)−k₁−1=6 or based on a configured offset with value O_(SB)^(DL)=5 (k₂=k₁+O_(SB) ^(DL)).

After eNB 102 configures to LC/CE UE 114 the N_(SB) ^(M-PDCCH) sub-bandsfor repetitions of an MPDCCH transmission, eNB 102 transmits and LC/CEUE 114 receives first R_(SB) ^(M-PDCCH) repetitions of an MPDCCHtransmission in the first sub-band. The next R_(SB) ^(M-PDCCH)repetitions are in the sub-band with the next higher index, among theconfigured sub-bands for repetitions of an MPDCCH transmission, with awrap-around to the lowest index when the highest index is reached.Equivalently, an index for a next sub-band for R_(SB) ^(M-PDCCH)repetitions of an MPDCCH transmission can be determined as (i+1)modN_(SB) ^(M-PDCCH) where i is the sub-band index for current R_(SB)^(M-PDCCH) repetitions of the MPDCCH transmission.

When eNB 102 does not configure to LC/CE UE 114 a first sub-band forfirst repetitions of an MPDCCH transmission, LC/CE UE 114 can implicitlydetermine a first sub-band for first R_(SB) ^(M-PDCCH) repetitions of anMPDCCH transmission based on a cell radio network temporary identifier(C-RNTI), or identity (ID), that eNB 102 configures to LC/CE UE 114. Forexample, as an index of a first sub-band can be equal to C-RNTImod(N_(SB) ^(DL)).

In another example, a set of sub-bands can be predetermined for a givenDL system BW and an index can indicate sub-bands from the set ofsub-bands. For example, a set of sub-bands can include 4 sub-band pairsand a 2-bit index can indicate one of the 4 sub-band pairs.

In a second approach, a configuration of a number of sub-bands forrepetitions of an MPDCCH transmission to LC/CE UE 114 can be in a systeminformation block (SIB) transmitted from eNB 102 using a same signalingmethod as described for the first approach. A determination by LC/CE UE114 of a first sub-band for first R_(SB) ^(M-PDCCH) repetitions of anMPDCCH transmission can be as described for the first approach, eitherexplicitly by RRC signaling from eNB 102 to LC/CE UE 114 or implicitlybased on another configuration to LC/CE UE 114 such as a C-RNTI or aglobal ID for LC/CE UE 114.

In case a CSS is supported for MPDCCH transmissions then, when SIB s arescheduled by MPDCCH transmitted in the CSS, respective sub-bands can beindicated in a master information block (MIB) and a first sub-band forfirst repetitions of an MPDCCH transmission can always be the lowerindexed sub-band with a next number of repetitions being in the sub-bandwith the next higher index; otherwise, the CSS sub-bands can beindicated in a SIB. The previously described approaches for signalingsub-bands for repetitions of an MPDCCH transmission can apply. To reducea number of bits required to indicate the sub-bands for CSS,predetermined sub-sets of the N_(SB) ^(DL) sub-bands can be considered.For example, one from four predetermined sub-sets of sub-bands can beindicated using 2 bits. When a single sub-set of sub-bands can exist andcan be determined by other means, such as Physical Cell ID (PCID) for aneNB, and no explicit signaling is needed. Further, the number of CSSsub-bands, N_(SB) ^(CSS), can be predetermined in the system operation,such as N_(SB) ^(CSS)=2 sub bands or N_(SB) ^(CSS)=4 sub-bands.

In order to enable repetitions of different MPDCCH transmissions in asame set of sub-bands, eNB 102 can configure to LC/CE UE 114 an index ofa first sub-band for a first number of repetitions of an MPDCCHtransmission. For a total N_(SB) ^(DL) DL sub-bands, eNB 102 canconfigure LC/CE UE 114 a first sub-band index using ┌log₂(N_(SB) ^(DL))┐bits. The remaining of N_(SB) ^(M-PDCCH) sub-band indexes can bedetermined by adding (modulo N_(SB) ^(DL)) a, predefined or configuredby ┌log₂(N_(SB) ^(DL))┐ bits in a SIB, offset O_(SB) ^(DL) to the firstsub-band index as previously described, for example in FIG. 11.Therefore, denoting by k₁, 0≤k₁<N_(SB) ^(DL), the index of the firstsub-band, the index of a second sub-band is k₂=(k₁+O_(SB) ^(DL))modN_(SB) ^(DL). For example, for a set that includes two sub-bands for anMPDCCH transmission, eNB 102 can configure LC/CE UE 114 to transmit afirst repetition in the first of the two sub-bands and eNB 102 canconfigure a second LC/CE UE to transmit a first repetition in the secondof the two sub-bands. Further, an explicit configuration can instead beavoided and LC/CE UE 114 can implicitly determine an index of a sub-bandto transmit first repetitions of an MPDCCH transmission as (C-RNTI)modN_(SB) ^(DL).

Repetitions for an MPDCCH transmission can also be in a subset ofconfigured sub-bands in order to maximize a number of repetitions in asame sub-band and apply DMRS filtering to improve channel estimation. Insuch case, repetitions for a first MPDCCH transmission to LC/CE UE 114can be in a first subset of configured sub-bands while repetitions for asecond MPDCCH transmission to LC/CE UE 114 can be in a second subset ofconfigured sub-bands, different than the first subset of configuredsub-bands, in order to enable LC/CE UE 114 to obtain CSI for everysub-band in the configured set of sub-bands. For example, when LC/CE UE114 is configured with N_(SB) ^(M-PDCCH) sub-bands for repetitions of anMPDCCH transmission, LC/CE UE 114 can monitor (presumed) repetitions fora first MPDCCH transmission in the first and third sub-bands and monitor(presumed) repetitions for a second MPDCCH transmission in the secondand fourth sub-bands. Equivalently, sub-bands for possible MPDCCHtransmissions can alternate within a configured set of sub-hands. TheeNB 102 may or may not actually transmit the first MPDCCH or the secondMPDCCH.

Configuration of Sub-Bands for PDSCH Transmission

In a first approach, eNB 102 configures LC/CE UE 114 same sub-bands forrepetitions of a PDSCH transmission and for repetitions of an MPDCCHtransmission. There is no separate (additional) configuration ofsub-bands for repetitions of a PDSCH transmission. For a determinationof a first sub-band for first R_(SB) ^(PDSCH) consecutive repetitionsper sub-band of a PDSCH transmission, two example implementations areprovided.

In a first example implementation, a first sub-band for first R_(SB)^(PDSCH) of a PDSCH transmission is same as a last sub band for R_(SB)^(M-PDCCH) consecutive repetitions of an MPDCCH transmission. The firstexample implementation provides a benefit that LC/CE UE 114 is able toimmediately receive PDSCH after detecting a respective DCI formatconveyed by an MPDCCH without LC/CE UE 114 incurring re-tuning delaythat is associated with receiving PDSCH in a first sub-band that isdifferent than a last sub-band of an MPDCCH reception scheduling thePDSCH.

In a second example implementation, a first sub-band for first R_(SB)^(PDSCH) repetitions of a PDSCH transmission is same as a next sub bandfor R_(SB) ^(M-PDCCH) repetitions of an MPDCCH transmission according toa frequency (sub-band) hopping pattern. The second exampleimplementation provides a benefit of combining MPDCCH and PDSCHtransmissions in a same frequency hopping pattern and simplifies amultiplexing of MPDCCH and PDSCH transmissions with same or differentnumbers of repetitions particularly when R_(SB) ^(PDSCH)=R_(SB)^(M-PDCCH). Moreover, when additional latency is provided to LC/CE UE114 for decoding a DCI format conveyed by an MPDCCH, a re-tuning delayis not an issue due to the additional decoding latency.

FIG. 12 illustrates a determination of sub-bands for repetitions of aPDSCH transmission based on sub-bands for repetitions of an MPDCCHtransmission according to this disclosure.

A same two sub-bands are used for repetitions of an MPDCCH transmissionand for repetitions of a PDSCH transmission to LC/CE UE 114. LC/CE UE114 first receives the MPDCCH over 2 SFs in the first sub-band 1210 andthen over 2 SFs in the second sub-band 1215. LC/CE UE 114 first receivesthe PDSCH over 4 SFs in the first sub-band 1220 and then over 4 SFs inthe second sub-band 1225. A switching period for re-tuning between RBsof different sub-bands is not shown for brevity.

In a second approach, eNB 102 independently configures LC/CE UE 114sub-bands for repetitions of a PDSCH transmission and sub-bands forrepetitions of an MPDCCH transmission. A first sub band for first R_(SB)^(PDSCH) repetitions of a PDSCH transmission is configured using arespective field in a DCI format conveyed by an MPDCCH and schedulingthe PDSCH transmission. For example, a 1-bit field in the DCI format canindicate whether a first sub-band for first R_(SB) ^(PDSCH) repetitionsof a PDSCH transmission is one of two predetermined sub-bands. Forexample, a field of ┌log₂(N_(SB) ^(DL))┐ bits can indicate any sub-bandin a DL system BW of N_(SB) ^(DL) sub-bands as a first sub band forfirst R_(SB) ^(PDSCH) repetitions of a PDSCH transmission. The remainingsub-bands for respective remaining repetitions for the PDSCHtransmission can be determined from, a predetermined or configured by┌log₂(N_(SB) ^(DL))┐ bits, offset relative to the first sub-band in asame manner as for determining remaining sub-bands for an MPDCCHtransmission based on a first respective sub-band.

A DCI format scheduling a PDSCH transmission can include an indicationof RBs in addition to including an indication of a first sub-band forfirst number of R_(SB) ^(PDSCH) repetitions for the PDSCH transmission.For example, for a DL system BW of 100 RBs, there can be N_(SB) ^(DL)=16sub-bands of N_(RB) ^(SB)=6 RBs and a sub-band can be indicated with┌log₂(N_(SB) ^(DL))┐=┌log₂(16)┐=4 bits in the DCI format. Within anindicated sub-band, a number of consecutive RBs can be indicated using┌log₂(N_(RB) ^(SB)(N_(RB) ^(SB)+1)/2)┐=5 bits. When an allocation of RBscan be restricted to be in a multiple of RBs, such as 2 RBs, a bit-mapof 3 bits suffices.

Configuration of Sub-Bands or RBs for PUSCH Transmission

Repetitions for a PUSCH transmission from LC/CE UE 114 to eNB 102 areconsidered to be in RBs or in fractions of RBs (unlike repetitions of anMPDCCH transmission or a PDSCH transmission that are considered to bewithin sub-bands of 6 RBs). The reason is that for a LC/CE UE that iscoverage limited and configured to transmit a PUSCH with repetitions, itis preferable for a transmission power to be concentrated in a smalltransmission BW in order to maximize a respective power spectraldensity. Configuration of RBs is subsequently considered for brevity butsame principles apply for configuration of sub-bands and of RBs withineach sub-band, for example as described for a PDSCH transmission.

In a first approach, a configuration of RBs for repetitions of a PUSCHtransmission from LC/CE UE 114 can be part of the configuration for RRCconnection setup of LC/CE UE 114 with eNB 102. The RRC connection setupcan be provided either by “message 4” of an initial random accessprocess or by a subsequent PDSCH. In addition to a configuration of RBsfor repetitions of a PUSCH transmission, eNB 102 configures to LC/CE UE114 a first RB for a first number of R_(RB) ^(PUSCH) repetitions for aPUSCH transmission in order to allow multiplexing of PUSCH transmissionsfrom different LC/CE UEs in different RBs during the same SFs.Therefore, eNB 102 indicates to LC/CE UE 114 a number of RBs M_(RB)^(PUSCH) for repetitions of a PUSCH transmission and a first RB for afirst number of repetitions of a PUSCH transmission.

In a first example, RBs for repetitions of a PUSCH transmission can beindicated using a bit-map having a size defined by the number of RBs inthe UL system BW wherein a binary ‘1’, for example, can indicate that aRB is used for a repetition of a PUSCH transmission. For example, for aUL system BW of 50 RBs, the bit-map size is 50 bits.

In a second example, when a number of M_(RB) ^(PUSCH) RBs used forrepetitions of a PUSCH transmission is restricted to be one from afinite set of numbers of RBs, such as for example 2 RBs, it is possibleto reduce a number of bits required for indicating the RBs used forrepetitions of a PUSCH transmission by using a combinatorial index r asit was previously described for the case of an MPDCCH transmission. Thecombinatorial index r corresponds to the RB index

{k_(i)}_(i = 0)^(M_(RB)^(PUSCH) − 1), (0 ≤ k_(i) ≤ M_(RB)^(UL), k_(i) < k_(i + 1))and is given by equation

$r = {{\sum\limits_{i = 0}^{M_{RB}^{PUSCH} - 1}{\left\langle \begin{matrix}{M_{RB}^{UL} - k_{i}} \\{M_{RB}^{PUSCH} - i}\end{matrix} \right\rangle\mspace{14mu}{where}\mspace{14mu}\left\langle \begin{matrix}x \\y\end{matrix} \right\rangle}} = \left\{ \begin{matrix}\begin{pmatrix}x \\y\end{pmatrix} & {x \geq y} \\0 & {x < y}\end{matrix} \right.}$is the extended binomial coefficient, resulting in unique label

$r \in {\left\{ {0,\ldots\mspace{14mu},{\begin{pmatrix}M_{RB}^{UL} \\M_{RB}^{PUSCH}\end{pmatrix} - 1}} \right\}.}$The number of bits needed to indicate the index r is

$\left\lceil {\log_{2}\begin{pmatrix}M_{RB}^{UL} \\M_{RB}^{PUSCH}\end{pmatrix}} \right\rceil.$For example, for M_(RB) ^(UL)=50 and M_(RB) ^(PUSCH)=2, the number ofbits is 11. When M_(RB) ^(PUSCH) is not predetermined in the systemoperation but also needed to be indicated among S_(PUSCH) possiblevalues, ┌log₂ S_(PUSCH)┐ additional bits are needed. For example, whenpossible values for M_(RB) ^(PUSCH) are 2 and 4, one additional bit isneeded.

A number of bits required to indicate RBs for repetitions of a PUSCHtransmission, using either the bit-map or the combinatorial indexapproach, can be reduced when the RBs are restricted to have apredefined symmetry that is determined by an offset relative to a firstRB that eNB 102 configures to UE 114. For example, for N_(RB)^(PUSCH)=2, when RB with index i, 0≤i<└M_(RB) ^(UL)/2┘, is configuredfor a PUSCH transmission, the RB with index i+└M_(RB) ^(UL)/2┘ (offsetof └M_(RB) ^(UL)/2┘ RBs) is also configured or, in another example, theRB with index M_(RB) ^(UL)−i−1 (mirrored RB from the other side of theUL BW) is also configured as a result of the predefined symmetry.Further, instead of the offset being predetermined relative to aconfigured first RB for a first number of repetitions of a PUSCHtransmission, the offset O_(RB) ^(UL) can also be configured by eNB 102to LC/CE UE 114 and consequently, for M_(RB) ^(PUSCH)=2, the RB withindex i+O_(RB) ^(UL) is also configured by eNB 102 to LC/CE UE 114 as aresult of the first configured RB with index i and the configured offsetO_(RB) ^(UL).

In a second approach, the configuration of RBs for repetitions of aPUSCH transmission to a LC/CE UE can be in a SIB transmitted from an eNBusing a same signaling method as described for the first approach. Adetermination by LC/CE UE 114 of a first RB for first R_(RB) ^(PUSCH)repetitions of a PUSCH transmission can be as described for the firstapproach, that is either by RRC signaling specific to LC/CE UE 114 orimplicit based on another configuration to LC/CE UE 114 such as a C-RNTIor a global ID for LC/CE UE 114.

Three implementations are disclosed for an indication of a first RB forfirst N_(RB) ^(PUSCH) repetitions of a PUSCH transmission. In a firstimplementation, a first RB for first R_(RB) ^(PUSCH) repetitions of aPUSCH transmission is indicated using a bit-map of size M_(RB) ^(PUSCH)bits.

In a second implementation, when a number of RBs M_(RB) ^(PUSCH) forrepetitions of a PUSCH transmission is same as a number of sub-bandsN_(SB) ^(M-PDCCH) for repetitions of an MPDCCH transmission, a RB forfirst R_(RB) ^(PUSCH) repetitions of a PUSCH transmission is the RB witha same index as a sub-band for first R_(SB) ^(M-PDCCH) repetitions of anMPDCCH transmission scheduling the PUSCH transmission. For example, forM_(RB) ^(PUSCH)=N_(SB) ^(M-PDCCH)=2, when first R_(SB) ^(M-PDCCH)repetitions for a MPDCCH scheduling a PUSCH transmission are in thefirst of the N_(SB) ^(M-PDCCH)=2 sub-bands, the first R_(RB) ^(PUSCH)repetitions of the PUSCH transmission are also in the first of theM_(RB) ^(PUSCH)=2 RBs. The second implementation provides the benefit ofcombining MPDCCH and PUSCH transmissions in a same frequency hoppingpattern and simplifies the multiplexing of MPDCCH and PUSCHtransmissions for different LC/CE UEs without requiring additionalsignaling to avoid PUSCH resource collisions.

In a third implementation, a first RB for first R_(RB) ^(PUSCH)repetitions of a PUSCH transmission is indicated using a respectivefield in a DCI format conveyed by an MPDCCH and scheduling the PUSCH andremaining RBs for repetitions of the PUSCH transmission are determinedfrom a predetermined or configured offset O_(RB) ^(UL). For example, foran UL system BW of 100 RBs, there can be N_(SB) ^(UL)=16 sub-bands, eachincluding N_(RB) ^(SB)=6 RBs, and a first sub-band can be indicated with┌log₂(N_(SB) ^(UL))┐=┌log₂(16)┐=4 bits in the DCI format. Within anindicated sub-band, a number of consecutive RBs can be indicated using┌log₂(N_(RB) ^(SB)(N_(RB) ^(SB)+1)/2)┐=5 bits.

Configuration of Sub-Bands or RBs for PUCCH Transmission

Considering that a PDSCH or an MPDCCH transmission to a LC/CE UE thatrequires CE is in slit bands of 6 RBs, at most └M_(RB) ^(DL)/6┘ LC/CEUEs can be scheduled respective PDSCHs in a same set of SFs. Therefore,for a maximum DL system BW of M_(RB) ^(DL)=100 RBs, at most 16 LC/CE UEsneed to transmit HARQ-ACK information in a PUCCH in response torespective PDSCH or MPDCCH receptions in a same set of SFs. As LC/CE UE114 receives only one data TB in a PDSCH, LC/CE UE 114 uses PUCCH Format1a to transmit respective HARQ-ACK information (see also REF 1). Since amultiplexing capacity for PUCCH Format 1a in 1 RB is typically largerthan 16 (see also REF 1), LC/CE UEs can be configured a same RB fortransmission of HARQ-ACK information in a PUCCH. Different RBs for PUCCHtransmission in a same SF can be configured to LC/CE UEs requiringdifferent CE levels due to respective path-loss differences in order toavoid near-far effects causing eNB 102 to be unable to detect a weakersignal due to presence of a stronger signal. A configuration ofdifferent RBs for PUCCH transmission corresponding to different CElevels can be by separate configuration per CE level of a correspondingPUCCH resource offset (see also REF 1 and REF 3).

A configuration of RBs for repetitions of a PUCCH transmission for eachCE level supported by eNB 102 can be informed by respective PUCCHresource offsets per CE level in a SIB as the RB can be common for allLC/CE UEs having a same CE level. The RBs can be restricted to besymmetric relative to the two sides of an UL system BW. For repetitionsof a PUCCH transmission in 2 RBs, wherein the first RB has index i andthe second RB has index M_(RB) ^(UL)−i−1, where 0≤i<└M_(RB) ^(UL)/2┘,only the index i needs to be signaled and this can be done with┌log₂(└M_(RB) ^(UL)/2┘)┐ bits. A RB where LC/CE UE 114 transmits firstR_(R) ^(PUCCH) repetitions of a PUCCH transmission can either be the RBwith the lowest index, or the RB index can be included in the SIB for arespective PUCCH repetition level (CE level), or the RB index can bedetermined according to the CE level wherein, for example, a lower RBindex, such as RB index i, is first used for R_(RB) ^(PUCCH) repetitionsof a PUCCH transmission for a first CE level and a higher RB index, suchas RB index M^(UL) _(RB)−i−1, is first used for N_(RB) ^(PUCCH)repetitions of a PUCCH transmission for a second CE level.

FIG. 13 illustrates RBs for repetitions of a PUCCH transmissionaccording to a first CE level and according to a second CE levelaccording to this disclosure.

PUCCH transmissions in a RB pair are supported for two different CElevels in a first RB 1300 and in a second RB 1305. A first LC/CE UEoperating with a first CE level transmits 4 repetitions of a PUCCH inSFs 0, 1, 2, and 3 in the first RB 1310 and transmits 4 repetitions ofthe PUCCH in SFs 4, 5, 6, and 7 in the second RB 1315 for a total of 8repetitions for the PUCCH transmission. A third LC/CE UE also operatingwith the first CE level transmits 4 repetitions of a PUCCH in SFs 8, 9,10, and 11 in the first RB 1320 and transmits 4 repetitions of the PUCCHin SFs 12, 13, 14, and 15 in the second RB 1325 for a total of 8repetitions for the PUCCH transmission. A second LC/CE UE operating witha second CE level transmits 4 repetitions of a PUCCH in SFs 0, 1, 2, and3 in the second RB 1330, transmits 4 repetitions of the PUCCH in SFs 4,5, 6, and 7 in the first RB 1332, transmits 4 repetitions of a PUCCH inSFs 8, 9, 10, and 11 in the second RB 1334, and transmits 4 repetitionsof the PUCCH in SFs 12, 13, 14, and 15 in the first RB 1336 for a totalof 16 repetitions for the PUCCH transmission. A switching period forre-tuning between RBs for repetitions of a PUCCH transmission is notshown for brevity.

One advantage of the structure in FIG. 13, where a number of consecutiverepetitions per RB for a PUCCH transmission is the same regardless ofthe total number of repetitions, is that this structure simplifiesmultiplexing in a same RB and in different SFs of PUCCHs for differentCE levels (different total number of repetitions) or even of differentUL channels (when N_(RB) ^(PUSCH)=N_(RB) ^(PUCCH)) for same or differentCE levels. A same structure can be used for repetitions of DL channeltransmission where a sub-band instead of a RB applies (and R_(SB)^(PDSCH)=R_(SB) ^(M-PDCCH)). A same RB hopping pattern/interval or asame sub-band hopping pattern/interval can also apply for different ULchannels or DL channels, respectively, or for different CE levels.Support of different CE levels for different LC/CE UEs or for differentchannels can be achieved through a different respective total number ofrepetitions. The values of R_(SB) ^(PDSCH), R_(SB) ^(M-PDCCH), R_(RB)^(PUSCH), and R_(RB) ^(PUCCH) can be configured to LC/CE UE 114 eitherby RRC or by a SIB from eNB 102 or be predefined in the systemoperation.

After LC/CE UE 114 determines RBs for repetitions of a PUCCHtransmission, LC/CE UE 114 needs to determine a PUCCH resource in theRBs. A differentiating factor among LC/CE UEs transmitting PUCCH in sameRBs in same SFs is the first sub-band or a last sub-band of anassociated MPDCCH reception. A PUCCH resource in a RB can then bedetermined as n_(PUCCH)=n_(SB,0)+N_(offset), where N_(offset) is a PUCCHresource offset and is configured by higher layer signaling for arespective CE level and n_(SB,0) is the sub-band index either for afirst or for a last repetition of an associated MPDCCH transmission forSPS release or n_(SB,0) is the sub-band index either for a firstrepetition or for last repetition of the associated PDSCH transmission.A PUCCH resource can be mapped to a cyclic shift and an orthogonalcovering code that are used for a PUCCH Format 1a transmission asdescribed in REF 1 and REF 3.

FIG. 14 illustrates a method for a LC/CE UE operating with CE todetermine a PUCCH resource for a transmission of HARQ-ACK informationaccording to this disclosure.

LC/CE UE 114 first determines RBs for a PUCCH transmission conveyingHARQ-ACK information 1410, for example as described in FIG. 13.Subsequently, LC/CE UE 114 determines a sub-band conveying the lastrepetition of an MPDCCH transmission associated with the HARQ-ACKinformation 1420. Finally, LC/CE UE 114 determines an index of aresource for a PUCCH transmission in the RBs 1430 wherein the index isequal to the index of the sub-band. The order of the steps 1410, 1420,and 1430 can be inter-changed but step 1420 precedes step 1430.

To avoid BW fragmentation, it is preferable to share a RB pair, indifferent SFs, among PUCCH Format 1a transmissions corresponding to twoCE levels. As MPDCCH/PDSCH transmissions are typically with repetitionswhen a respective PUCCH Format 1a transmission is with repetitions, dueto the typically better link budget for PUCCH Format 1a relative toMPDCCH, PDSCH, or PUSCH, and as PUCCH Format 1a transmissions from allUEs having a same last SF for respective PDSCH transmissions can bemultiplexed in a same RB, the same RB can be used for first repetitionsof a PUCCH Format 1a transmission from all UEs receiving a last PDSCHrepetition in a same last SF and transmitting PUCCH Format 1a with asame number of repetitions.

A RB for first repetitions of a PUCCH Format 1a transmission is the oneindicated by the CE level specific PUCCH resource offset. For a total ofM_(RB) ^(UL) NBs, when eNB 102 configures to LC/CE UE 114 RBi,0≤i≤┌M_(RB) ^(UL)/2┐−1, then M_(RB) ^(UL)−i−1 is used for frequencyhopping of the PUCCH Format 1a transmission after the first repetitions.When a same PUCCH resource offset N_(offset) is indicated for two CElevels corresponding to two respective PUCCH Format 1a repetitionnumbers, a RB for first PUCCH Format 1a repetitions for the second CElevel is RB M_(RB) ^(UL)−i−1 where a same frequency hopping interval isused for both CE levels. This enables using a same RB pair totime-division multiplex PUCCH Format 1a transmissions for the two CElevels. This also enables using same RB pairs to time-division multiplexrepetitions of PDSCH transmissions with different repetition numbers.For example, using RB indexing within a sub-band and not across theentire UL system BW, when PUCCH Format 1a repetitions for the smallernumber of repetitions are in RB j of sub-band i, PUCCH Format 1arepetitions for the larger number of repetitions are in RB j of sub-bandN_(SB) ^(UL)−i−1.

Therefore, when higher layer signaling in a SIB indicates a sub-bandwith index i,0≤i≤┌N_(SB) ^(UL)/2┐−1, for PUCCH Format 1a transmission,the two sub-bands for frequency hopping are the ones with indexes i andN_(SB) ^(UL)−i. When higher layer signaling in a SIB indicates a same RBin a sub-band with index i,0≤i≤┌N_(SB) ^(UL)/2┐−1, for PUCCH Format 1atransmission with for two CE levels, a first repetition for a PUCCHFormat 1a transmission with a first CE level is in sub-band with index iand a first repetition for a PUCCH Format 1a transmission with a secondCE level is in sub-band with index M_(SB) ^(UL)−i−1; otherwise, thefirst repetition is always in sub-band with index i.

Multiplexing Repetitions for Transmission of Channels with FrequencyHopping and Repetitions for Transmission of Channels without FrequencyHopping in Same Frequency Resources

A transmission of a DL channel (MPDCCH, PDSCH) or of an UL channel(PUCCH, PUSCH) can also be localized in a same sub-band or RB instead ofusing frequency hopping among sub-bands or RBs, respectively. Forexample, based on a sub-band CSI report from LC/CE UE 114, whenavailable, eNB 102 can determine that LC/CE UE 114 experiences betterSINR in a first sub-band than in a second sub-band and then eNB 102 canconfigure LC/CE UE 114 to receive repetitions of a PDSCH transmissiononly in the first sub-band (no frequency hopping across sub-bands)instead of both in the first and second sub-bands using frequency(sub-band) hopping. For example, based on a SINR estimate obtained froma DMRS when LC/CE UE 114 transmits repetitions of a PUSCH in a first RBand in a second RB using frequency (RB) hopping, eNB 102 can determinethat LC/CE UE 114 experiences better SINR in the second RB than in thefirst RB and then configure LC/CE UE 114 to transmit repetitions of aPUSCH transmission only in the second RB.

In order to enable multiplexing of repetitions for a DL channel or an ULchannel transmission in a single sub-band or in a single RB,respectively, with repetitions for a DL channel or an UL channeltransmission in multiple sub-bands or multiple RBs that include thesingle sub-band or the single RB, respectively, this disclosure providesfor LC/CE UE 114 to be configured for intermittent reception ofrepetitions for a DL channel transmission or intermittent transmissionof repetitions for an UL channel transmission.

FIG. 15 illustrates multiplexing of repetitions for PUSCH transmissions,with and without frequency hopping, over 2 RBs according to thisdisclosure.

A first LC/CE UE, a second LC/CE UE, and a third LC UE are configuredrepetitions for respective PUSCH transmissions in a first RB 1500 and ina second RB 1505. The first LC/CE UE is configured to transmit 16repetitions, using frequency hopping between the first RB and the secondRB, in first four SFs 1510, in second four SFs 1512, in third four SFs1514, and in fourth four SFs 1516. The second LC/CE UE is configured totransmit 8 repetitions only in the first RB in first four SFs 1520 andin second four SFs 1525. The second UE suspends repetitions of the PUSCHtransmission in the second four SFs in the first RB. The third LC/CE UEis configured to transmit 8 repetitions only in the second RB in secondfour SFs 1530 and in fourth four SFs 1535. The third UE suspendsrepetitions of the PUSCH transmission in the first four SFs and in thethird four SFs in the second RB.

Therefore, for a channel transmission with R repetitions, a number of Xrepetitions are transmitted in a same sub-band or in same one or moreRBs, and next X repetitions are transmitted in a different sub-band orin different one or more RBs, respectively. For a channel transmission,a configuration of X can be per number R of repetitions or can bepredetermined in the system operation. The configuration can be, forexample, by eNB 102 signaling in a SIB two bits indicating four states(‘00’, ‘01’, ‘10’, ‘11’). A first state can indicate X=R (this disablesfrequency hopping and allows for frequency selective scheduling), asecond state can indicate X=R/2, a third state can indicate X=R/4, and afourth state can indicate X=R/8. Some states can remain without amapping to an X value when such a mapping is not applicable (forexample, when R=4, the value of X=R/8 is not applicable). For example,X=R/4 for R=8 and X=R/2 for R=4 in order to enable a LC/CE UE operatingwith a “small” CE level to simultaneously monitor different numbers ofrepetitions. For example, for a PDSCH transmission with repetitions, X=Rto enable frequency-selective scheduling and X=R/2 otherwise when eNB102 supports only one CE level. A configurable value for X per CE levelcan enable eNB 102 to fully control, according to the eNB's schedulingstrategy and supported CE levels, tradeoffs associated with multiplexingchannel transmissions with different repetition numbers, transmissionlatency due to retuning, and number of required repetitions fordifferent CE levels.

Various embodiments of this disclosure provide combining repetitions foran MPDCCH, PDSCH, PUSCH, or PUCCH transmission.

Repetitions for an MPDCCH, PDSCH, PUSCH, or PUCCH transmission need toprovide improved respective reception reliability especially for PUSCHor PUCCH transmission as this can affect a required number ofrepetitions and power consumption for LC/CE UE 114, while also enablingsimple receiver architecture especially for MPDCCH or PDSCH reception atLC/CE UE 114 as this can affect a cost for LC/CE UE 114. For brevity,PDSCH transmission is subsequently considered but same arguments applyfor an MPDCCH, PUSCH, or PUCCH transmission.

PDSCH reception reliability can be improved by using differentredundancy versions (RVs) among repetitions of a PDSCH transmission insuccessive SFs where the repetitions are transmitted. This is becauseusing different RVs improves a diversity of a data TB as different RVscorrespond to different versions of the encoded data TB and containdifferent combinations of systematic and forward-error correcting bits(parity bits). For example, using different RVs among repetitions of aPUSCH transmission in successive SFs is considered for PUSCH repetitions(see also REF 3) where, for four RVs, a pattern of 0, 2, 3, 1 appliesamong successive repetitions.

One disadvantage from using successive (different) RVs in respectivesuccessive repetitions of a PDSCH transmission relates to LC/CE UE 114receiver implementation required for combining the repetitions of thePDSCH transmission. Due to the use of different RVs in successive SFs,combining of data symbols needs to occur after demodulation and prior todecoding (at a log-likelihood ratio (LLR) symbol level). For a LC/CE UE114 receiver implementation that avoids buffering symbols prior todemodulation over a number of SFs in order to reduce cost, demodulationof data symbols in a SF needs to be based only on a channel estimateobtained from a RS, such as a CRS or a DMRS, received in the respectiveSF and in earlier SFs from R_(SB) ^(PDSCH) corresponding to consecutiverepetitions in a same sub-band. An inability to combine RS from up toR_(SB) ^(PDSCH) successive SFs in a sub-band for demodulating datasymbols limits the accuracy of a channel estimate used for thedemodulation.

To avoid the disadvantage from using successive RVs in respectivesuccessive repetitions of a PDSCH transmission, in a first realization asame RV can be used for successive repetitions of the PDSCH transmissionin a sub-band and different RVs can be used for repetitions of the PDSCHtransmission in different sub-bands (as in FIG. 16). In a secondrealization a same RV can be used for a number of successive repetitionsof a PDSCH transmission in a sub-band and a different RV can be used fora next number of successive repetitions of the PDSCH transmission in thesub-band (as in FIG. 17).

Using a same RV in R_(SB) ^(PDSCH) successive SFs in a sub-band enablescombining data symbols prior to demodulation (I/Q-level combining) overa number of SFs without a need to buffer data symbols over the number ofSFs prior to demodulation, and also enables combining RS symbols overthe number of SFs for improved accuracy of a channel estimate used fordemodulation of data symbols (a same scrambling sequence is also assumedto apply over the number of SFs where same RV is used in order to enableI/Q-level symbol combining). This improved accuracy can in turn providesignificant gains in a reception reliability of a data TB, particularlyconsidering a low SINR that is experienced by LC/CE UE 114 when LC/CE UE114 requires operation with CE, and a reduction in a number of requiredrepetitions to achieve a target reception reliability for the data TB.

FIG. 16 illustrates a first realization for a use of RVs for repetitionsof a PDSCH transmission in a sub-band and in different sub-bandsaccording to this disclosure.

LC/CE UE 114 receives repetitions of a PDSCH transmission over a firstsub-band 1600 and over a second sub-band 1605. In a first realization,there are four successive repetitions of a PDSCH transmission inrespective SFs in one sub-band, such as a second sub-band, 1610 followedby another four successive repetitions of the PDSCH transmission inrespective SFs in another sub-band, such as a first sub-band, 1620followed by another four successive repetitions of the PDSCHtransmission in respective SFs in the second sub-band, 1630 and finallyfollowed by another four successive repetitions of the PDSCHtransmission in respective SFs in the first sub-band 1640. A same RV,RV0, and a same scrambling sequence is used for each of the first fourrepetitions 1610 to enable RS combining or I/Q symbol data combining,such as averaging, over all respective SFs prior to demodulation.Subsequently, demodulation can be performed on the combined data using achannel estimate obtained from the combined RS. Similar, same RVs, suchas RV2, RV3, and RV1, and respective same scrambling sequences can beused in each of the second 1620, third 1630, or fourth 1640 fourrepetitions, respectively, and further processing of the receivedrepetitions can be as for the first four repetitions. After datademodulation for each quadruplet of repetitions, demodulated data can becombined prior to decoding and then be decoded by LC/CE UE 114.

FIG. 17 illustrates a second realization for use of RVs for repetitionsof a PDSCH transmission in a sub-band and in different sub-bandsaccording to this disclosure.

LC/CE UE 114 receives repetitions of a PDSCH transmission over a firstsub-band 1700 and over a second sub-band 1705. In a second realization,there are eight successive repetitions of a PDSCH transmission inrespective SFs in one sub-band, such as a second sub-band, followed byanother eight successive repetitions of the PDSCH transmission inrespective SFs in another sub-band, such as a first sub-band. A same RV,RV0, and a first scrambling sequence are used in each of the first fourrepetitions 1710 and a same RV, RV2, and a second scrambling sequenceare used in each of the second four repetitions 1720 in the secondsub-band to enable data combining, such as averaging, over respectivefour SFs for a same RV prior to demodulation. Similar, a same RV, RV3,and a third scrambling sequence are used in each of the third fourrepetitions 1730 and a same RV, RV1, and a fourth scrambling sequenceare used in each of the fourth four repetitions 1740 in the firstsub-band to enable data combining prior to demodulation (I/Q data symbolcombining) over respective four SFs for a same RV prior to demodulation.Subsequently, demodulation can be performed on the combined data for asame RV per quadruple of SFs using a channel estimate obtained from thecombined RS over a number of SFs such as 4 SFs. After data demodulationfor each quadruplet of four repetitions, the demodulated data can becombined prior to decoding and then be decoded.

One advantage of the second realization over the first realization isthat only a single re-tuning to a different sub-band is needed, insteadof 3 re-tunings to different sub-bands, for a PDSCH transmission with 16repetitions. Either of the two realizations can also apply for MPDCCHtransmissions, and for PUSCH or PUCCH transmissions. Using a same RVover four repetitions provides a balance between gains from improvedchannel estimation due to I/Q symbol level combining prior todemodulation for the data symbols and gains from coding diversity due toa use of different RVs across repetitions. A number of repetitions thatuse a same RV can be configured to a LC/CE UE by an eNB, or can bedetermined in the system operation, for example as being fixed to avalue of four, or as being one-half of a total number of successiverepetitions in the sub-band.

Various embodiments of this disclosure provide time-frequency sub-bandhopping or RB hopping.

Prior to LC/CE UE 114 being configured by eNB 102 sub-bands for MPDCCHor PDSCH reception (or sub-bands/RBs for PUCCH or PUSCH transmission),LC/CE UE 114 needs to determine such sub-bands by other means. Forexample, when CSS is not supported for MPDCCH transmissions schedulingSIB-1 transmission (SIB-1 is a first SIB from multiple SIBs) andsub-bands for SIB-1 transmission are not signaled in a MIB, LC/CE UE 114needs to implicitly determine such sub-bands and respective SFs in orderto receive a PDSCH conveying the SIB-1.

Implicit determination of sub-bands and SFs for MPDCCH or PDSCHreception can be based on parameters such as the DL system BW that LC/CEUE 114 can obtain from a MIB or an identity (PCID) of eNB 102 that LC/CEUE 114 can determine after detection PSS/SSS (see also REF 1). As anumber of PCIDs can be large, such as 504, and a number of sub-bands canbe small, such as 8, it is unavoidable that same sub-bands for a MPDCCHCSS or for a PDSCH conveying, for example, a SIB-1 are used by eNBs withdifferent PCIDs. For example, for 2 sub-bands allocated to MPDCCH CSS orto PDSCH out of a total of 8 sub-bands, there are

$\begin{pmatrix}8 \\2\end{pmatrix} = 28$possible combinations that need to be shared among 504 PCIDs. Therefore,without specific network planning to avoid having PCIDs from neighboringeNBs mapped to same sub-bands or SFs, neighboring eNBs can use samesub-bands or SFs to transmit MPDCCH or PDSCH when the sub-bands or theSFs are not explicitly signaled but are instead determined as a functionof the PCID. Such sub-band collisions among neighboring eNBs can have adetrimental interfering effect when LC/CE UE 114 is located near aneighboring eNB.

To minimize collisions of sub-bands (or RBs) or SFs used for a CSS orfor PDSCH transmissions, sub-band hopping in the time domain orrandomization of SFs used for a CSS of for PDSCH transmissions canapply. For example, a function having as arguments a SFN of a frame, aSF index within a frame, a PCID, and a DL system BW, can be used todetermine a location of a sub-band in a SF or to determine the SFs for aSIB-1 transmission.

FIG. 18 illustrates a use of hopping to determine sub-bands for a PDSCHtransmission according to this disclosure.

After PSS/SSS and MIB detection, LC/CE UE 114 determines a PCID for eNB102, a DL system BW, a SFN, and a SF index. Based on this information,LC/CE UE 114 determines location in a DL system BW for a sub-band 1810,1815 that eNB 102 uses to transmit a PDSCH conveying, for example, aSIB-1. At a next frame and for a same SF index, a location for thesub-band that eNB 102 uses to transmit the PDSCH is different 1820,1825.

Further, based on a PCID, only a subset of SFs per frame or a subset offrames can be used for repetitions of a channel transmission such as aSIB-1 transmission. The subset of SFs can additionally vary acrossframes. For example, in a FDD system, only a first (SF0), fifth (SF4),sixth (SF5), and tenth (SF9) SFs per frame can be guaranteed to alwayssupport repetitions of a SIB-1 transmission. Repetitions of a SIB-1transmission can be, for example, in two of the four SFs per framewhere, for example, the two SFs can be contiguous in time resulting tothe pairs (SF9, SF0) and (SF4, SF5). First two repetitions of a SIB-1transmission can be in (SF9, SF0), second two repetitions of a SIB-1transmission can be in (SF4, SF5), third two repetitions of a SIB-1transmission can be in (SF4, SF5), fourth two repetitions of a SIB-1transmission can be in (SF9, SF0), and so on. The hopping among SF pairscan be based on a pseudorandom pattern having as components the PCID,the SFN, and the 2 pairs of SFs. In another example, all SFs per framecan be used for repetitions of a SIB-1 transmission and frames withrepetitions of the SIB-1 transmission can have a pseudorandom patternand an average periodicity or be predetermined based on the PCID. Forexample, a first predetermined set of SFs can be used to transmit SIB-1for a first set of PCIDs, such as odd PCIDs, and a second predeterminedset of SFs can be used to transmit SIB-1 for a first set of PCIDs, suchas even PCIDs. In another example, repetitions of a SIB-1 transmissioncan be based on a pseudorandom pattern that limits the repetitions bothin a subset of available SFs per frame and in a subset of availableframes per system frame number cycle of 1024 frames. The pseudorandompattern is known to LC/CE UE 114 in advance. A joint time-frequencyhopping pattern can also be defined having as parameters the PCID, theSFN, the number of sub-bands available for SIB-1 transmission, and the 2pairs of SFs.

FIG. 19 illustrates a use of a pseudorandom subset of SFs per frame forrepetitions of a channel transmission according to this disclosure.

After PSS/SSS and MIB detection, LC/CE UE 114 determines a PCID for eNB102, a DL system BW, a SFN, and a SF index. Based on this informationand on predetermined knowledge of SFs per frame that support repetitionof a transmission, such as a SIB-1 transmission, and of a pseudorandompattern, LC/CE UE 114 determines location in a DL system BW for asub-band and two SFs in a first frame for two repetitions of the SIB-1transmission 1910, determines location in a DL system BW for a sub-bandand two SFs in a first frame and a second frame for two repetitions ofthe SIB-1 transmission 1920, and determines location in a DL system BWfor a sub-band and two SFs in a second frame and a third frame for tworepetitions of the SIB-1 transmission 1930. Although repetitions of theSIB-1 transmission are shown to occur in consecutive frames, they canoccur intermittently across frames according to a predetermined pattern.

To aid the Patent Office and any readers of any patent issued on thisapplication in interpreting the claims appended hereto, applicants wishto note that they do not intend any of the appended claims or claimelements to invoke 35 U.S.C. § 112(f) unless the words “means for” or“step for” are explicitly used in the particular claim. Use of any otherterm, including without limitation “mechanism,” “module,” “device,”“unit,” “component,” “element,” “member,” “apparatus,” “machine,”“system,” “processor,” or “controller,” within a claim is understood bythe applicants to refer to structures known to those skilled in therelevant art and is not intended to invoke 35 U.S.C. § 112(f).

Although the present disclosure has been described with exampleembodiments, various changes and modifications can be suggested to oneskilled in the art. It is intended that the present disclosure encompasssuch changes and modifications that fall within the scope of theappended claims.

What is claimed is:
 1. An apparatus of a base station comprising: atransceiver; and at least one processor operably coupled to thetransceiver; wherein the at least one processor is configured to controlthe transceiver to transmit or receive signals in consecutive subframes(SFs), and wherein a redundancy version (RV) numbered as 0 is applied toa physical downlink shared channel (PDSCH) transmitted in first fourconsecutive SFs of the consecutive SFs, wherein a RV numbered as 2 isapplied to a PDSCH transmitted in second four consecutive SFs of theconsecutive SFs, wherein a RV numbered as 3 is applied to a PDSCHtransmitted in third four consecutive SFs of the consecutive SFs, andwherein a RV numbered as 1 is applied to a PDSCH transmitted in fourthfour consecutive SFs of the consecutive SFs.
 2. The apparatus of claim1, wherein the at least one processor is further configured to controlthe transceiver to transmit or receive signals in other consecutive SFs,and wherein a RV numbered as 0 is applied to a physical uplink sharedchannel (PUSCH) transmitted in first four consecutive SFs of the otherconsecutive SFs, wherein a RV numbered as 2 is applied to a PUSCHtransmitted in second four consecutive SFs of the other consecutive SFs,wherein a RV numbered as 3 is applied to a PUSCH transmitted in thirdfour consecutive SFs of the other consecutive SFs, and wherein a RVnumbered as 1 is applied to a PUSCH transmitted in fourth fourconsecutive SFs of the other consecutive SFs.
 3. The apparatus of claim1, wherein the at least one processor is further configured to controlthe transceiver to transmit system information for configuring aphysical uplink channel resource offset for each of coverage enhancement(CE) levels.
 4. The apparatus of claim 3, wherein the at least oneprocessor is further configured to control the transceiver to transmitsystem information for configuring the CE levels.
 5. An apparatus of auser equipment comprising: a transceiver; and at least one processoroperably coupled to the transceiver; wherein the at least one processoris configured to control the transceiver to transmit or receive signalsin consecutive subframes (SFs), and wherein a redundancy version (RV)numbered as 0 is applied to a physical downlink shared channel (PDSCH)transmitted in first four consecutive SFs of the consecutive SFs,wherein a RV numbered as 2 is applied to a PDSCH transmitted in secondfour consecutive SFs of the consecutive SFs, wherein a RV numbered as 3is applied to a PDSCH transmitted in third four consecutive SFs of theconsecutive SFs, and wherein a RV numbered as 1 is applied to a PDSCHtransmitted in fourth four consecutive SFs of the consecutive SFs. 6.The apparatus of claim 5, wherein the at least one processor is furtherconfigured to control the transceiver to transmit or receive signals inother consecutive SFs, and wherein a RV numbered as 0 is applied to aphysical uplink shared channel (PUSCH) transmitted in first fourconsecutive SFs of the other consecutive SFs, wherein a RV numbered as 2is applied to a PUSCH transmitted in second four consecutive SFs of theother consecutive SFs, wherein a RV numbered as 3 is applied to a PUSCHtransmitted in third four consecutive SFs of the other consecutive SFs,and wherein a RV numbered as 1 is applied to a PUSCH transmitted infourth four consecutive SFs of the other consecutive SFs.
 7. Theapparatus of claim 5, wherein the at least one processor is furtherconfigured to control the transceiver to receive system information forconfiguring a physical uplink channel resource offset for each ofcoverage enhancement (CE) levels.
 8. The apparatus of claim 7, whereinthe at least one processor is further configured to control thetransceiver to receive system information for configuring the CE levels.9. A method for operating a base station, comprising: transmitting orreceiving signals in consecutive subframes (SFs), wherein a redundancyversion (RV) numbered as 0 is applied to a physical downlink sharedchannel (PDSCH) transmitted in first four consecutive SFs of theconsecutive SFs, wherein a RV numbered as 2 is applied to a PDSCHtransmitted in second four consecutive SFs of the consecutive SFs,wherein a RV numbered as 3 is applied to a PDSCH transmitted in thirdfour consecutive SFs of the consecutive SFs, and wherein a RV numberedas 1 is applied to a PDSCH transmitted in fourth four consecutive SFs ofthe consecutive SFs.
 10. The method of claim 9, further comprising:transmitting or receiving signals in other consecutive SFs, and whereina RV numbered as 0 is applied to a physical uplink shared channel(PUSCH) transmitted in first four consecutive SFs of the otherconsecutive SFs, wherein a RV numbered as 2 is applied to a PUSCHtransmitted in second four consecutive SFs of the other consecutive SFs,wherein a RV numbered as 3 is applied to a PUSCH transmitted in thirdfour consecutive SFs of the other consecutive SFs, and wherein a RVnumbered as 1 is applied to a PUSCH transmitted in fourth fourconsecutive SFs of the other consecutive SFs.
 11. The method of claim 9,further comprising: transmitting system information for configuring aphysical uplink channel resource offset for each of coverage enhancement(CE) levels.
 12. The method of claim 11, further comprising:transmitting system information for configuring the CE levels.
 13. Amethod for operating a user equipment, comprising: transmitting orreceiving signals in consecutive subframes (SFs), wherein a redundancyversion (RV) numbered as 0 is applied to a physical downlink sharedchannel (PDSCH) transmitted in first four consecutive SFs of theconsecutive SFs, wherein a RV numbered as 2 is applied to a PDSCHtransmitted in second four consecutive SFs of the consecutive SFs,wherein a RV numbered as 3 is applied to a PDSCH transmitted in thirdfour consecutive SFs of the consecutive SFs, and wherein a RV numberedas 1 is applied to a PDSCH transmitted in fourth four consecutive SFs ofthe consecutive SFs.
 14. The method of claim 13, further comprising:transmitting or receiving signals in other consecutive SFs, and whereina RV numbered as 0 is applied to a physical uplink shared channel(PUSCH) transmitted in first four consecutive SFs of the otherconsecutive SFs, wherein a RV numbered as 2 is applied to a PUSCHtransmitted in second four consecutive SFs of the other consecutive SFs,wherein a RV numbered as 3 is applied to a PUSCH transmitted in thirdfour consecutive SFs of the other consecutive SFs, and wherein a RVnumbered as 1 is applied to a PUSCH transmitted in fourth fourconsecutive SFs of the other consecutive SFs.
 15. The method of claim13, further comprising: receiving system information for configuring aphysical uplink channel resource offset for each of coverage enhancement(CE) levels.
 16. The method of claim 15, further comprising: receivingsystem information for configuring the CE levels.